CHANGES IN THE CHEMICAL STRUCTURE OF THERMALLY TREATED WOOD

Changes in the chemical structure of hornbeam and uludag fir woods during thermal treatment were investigated at three temperatures (170, 190, and 210 oC) and three durations (4, 8, and 12 hours). After thermal treatment, the extents of degradation in the chemical structure of the samples were determined, and the effects on the chemical composition of hornbeam wood and uludag fir wood were investigated. The data obtained were analyzed using variance analysis, and Tukey’s test was used to determine the changes in the chemical structure of uludag fir and hornbeam woods. The results showed that heating wood permanently changes several of its chemical structures and that the changes are mainly caused by thermal degradation of wood polymers. It was found that decreasing of the cellulose and holocelluloses ratio had a favorable effect on the interaction of the wood with moisture. According to the obtained results, hornbeam wood is affected more than uludag fir wood. For each wood, the maximum decreases of holocellulose and α-cellulose were found at 210oC for 12 hours, and the maximum increase of lignin occurred at the same treatment combination

The density, compression strength and surface hardness of heat treated hornbeam (Carpinus betulus ) wood

The heat treatment of wood is an environment-friendly method for wood preservation. The heat treatment process only uses steam and heat, and no chemicals or agents are applied to the material during the process. Tests have shown no harmful emissions are apparent when working with the ma-terial. This process improves wood’s resistance to decay and its dimensional stability. In this study, the density, compression strength and hardness of heat treated hornbeam (Carpinus betulus L.) wood were investigated. Wood specimens that had been conditioned at 65% relative humidity and 20 ºC were subjected to heat treatment at 170, 190, and 210 ºC for 4, 8, and 12 hrs. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. The results showed that the decreases of compression strength and hardness were related to the extent of density loss. Both compression strength and hardness decreased with the increasing temperatures and durations of the heat treatment. While the maximum density loss observed was 16.12% at 210 ºC and 12 hour, at these heat-treatment conditions, the compression strength approximately decreased 30% and hardness values in tangential, radial, and longitudinal directions approximately decreased by 55%, 54%, and 38%, respectively. Hence, it was concluded that there might be a relationship between changes of these wood properties.

Partial rupture of the quadriceps muscle in a child

<p>Abstract</p> <p>Background</p> <p>The quadriceps femoris muscle ruptures usually occur in the middle-aged population. We present a 4-year-old patient with partial rupture of the quadriceps femoris muscle. To our knowledge, this is the youngest patient reported with a quadriceps femoris muscle rupture.</p> <p>Case Presentation</p> <p>A 4-year-old girl admitted to our clinic with left knee pain and limitation in knee movements. Her father reported that she felt pain while jumping on sofa. There was no direct trauma to thigh or knee. We located a palpable soft tissue swelling at distal anterolateral side of thigh. The history revealed that 10 days ago the patient was treated for upper tract respiratory infection with intramuscular Clindamycin for 7 days. When we consulted the patient with her previous doctor and nurse, we learnt that multiple daily injections might be injected to same side of left thigh. MRI showed a partial tear of vastus lateralis muscle matching with the injection sites. The patient treated with long leg half-casting for three weeks. Clinical examination and knee flexion had good results with conservative treatment.</p> <p>Conclusions</p> <p>Multiple intramuscular injections may contribute to damage muscles and make prone to tears with muscle contractions. Doctors and nurses must be cautious to inject from different parts of both thighs.</p

Kompoziti visoke gustoće na bazi polietilena ojačani toplinski modificiranim drvom

This study investigated the effect of untreated and heat-treated ash and black pine wood flour concentrations on the selected properties of high density polyethylene (HDPE) composites. HDPE and wood flour were used as thermoplastic matrix and filler, respectively. The blends of HDPE and wood fl our were compounded using single screw extruder and test samples were prepared through injection molding. Mechanical properties like tensile strength (TS), tensile modulus (TM), elongation at break (EatB), fl exural strength (FS), fl exural modulus (FM) and impact strength (IS) of manufactured composites were determined. Wood fl our concentrations have significantly increased density, FS, TM and FM and hardness of composites while reducing TS, EatB and IS. Heat-treated ash and black pine fl our reinforced HDPE composites had higher mechanical properties than untreated ones. Composites showed two main decomposition peaks; one coming from ash wood flour (353-370 °C) and black pine wood fl our (373-376 °C), the second one from HDPE degradation (469-490 °C). SEM images showed improved dispersion of heat-treated ash and black pine wood flour. The obtained results showed that both the untreated and heat-treated ash/black pine wood flour have an important potential in the manufacture of HDPE composites.U radu je opisano istraživanje utjecaja koncentracije drvnog brašna od nemodifi ciranog i toplinski modificiranog drva jasena i crnog bora na odabrana svojstva kompozita visoke gustoće na bazi polietilena (HDPE). HDPE i drvno brašno upotrijebljeni su kao termoplastična matrica i punilo. Mješavine HDPE-a i drvnog brašna pripremljene su uz pomoć ekstrudera s jednim vijkom, a ispitni su uzorci izrađeni injekcijskim prešanjem. Istraživanjem su određena mehanička svojstva proizvedenih kompozita poput vlačne čvrstoće (FS), modula elastičnosti pri vlačnom ispitivanju (FM), istezanja pri lomu (EatB), čvrstoće na svijanje (FS), modula elastičnosti pri tlačnom ispitivanju (FM) i udarne čvrstoće (IS). Koncentracije drvnog brašna značajno su povećale gustoću, tvrdoću, FS, TM i FM, a smanjile TS, EatB i IS. HDPE kompoziti ojačani drvnim brašnom od toplinski modifi ciranog drva jasena i crnog bora imali su bolja mehanička svojstva od kompozita ojačanih drvnim brašnom od nemodifi ciranog drva jasena i crnog bora. Kompoziti su pokazali dva glavna područja razgradnje: prvo, razgradnju drvnog brašna drva ariša (353 – 370 °C) i drvnog brašna drva crnog bora (373 – 376 °C) te, drugo, razgradnju HDPE-a (469 – 490 °C). SEM slike potvrdile su poboljšanu raspodjelu drvnog brašna od toplinski modifi ciranog drva jasena i crnog bora. Rezultati su pokazali da drvno brašno od nemodifi ciranoga i toplinski modifi ciranog drva jasena i crnog bora imaju velik potencijal u proizvodnji HDPE kompozita

THE INFLUENCE OF MASS LOSS ON THE MECHANICAL PROPERTIES OF HEAT-TREATED BLACK PINE WOOD

Heat has been a method used to dry and modify the properties of wood since ancient times. Nowadays, heat is used as industrial processes for the same reason. Treatment at temperatures above 150 degrees C can change the color of wood, improve its resistance to biodegradation, and enhance its dimensional stability. However, loss in the mechanical strength of wood may also occur, and this means heat-treated wood cannot be used in a broad range of products. This article investigates the mass loss, specific gravity, compression, and bending-strength of heat-treated Camiyani Black Pine wood at temperatures of 160 degrees C, 180 degrees C and 200 degrees C for 2 and 6 hours. The results show that increasing temperatures decreased specific gravity, compression, and bending strength of the specimens, whereas mass loss increased

Some Physical Properties of Heat-Treated Hornbeam (Carpinus betulus L.) Wood

Thermal treatment of wood alters its structure due to degradation of wood polymers (cellulose, hemicellulose, and lignin), so the physical properties of wood are either improved or worsen. In this study, the effect of thermal treatment on density, equilibrium moisture content (EMC), and color of hornbeam wood was investigated. The color and density (air-dry and oven-dry density) were determined for the control and heat-treated samples, as well as their equilibrium moisture content at relative humidities of 35, 50, 65, 80, and 95\%. The data showed that thermal treatment resulted mainly in darkening of the wood and the reduction of its density and EMC. It was found that the treatment temperature had a much more significant impact on color changes than the duration of the treatment. Generally, heat-treated wood color becomes darker than nontreated wood, so it can be used as decorative material. Because the EMC is lower, the heat-treated wood can be used in saunas and pool sides. Also, heat-treated wood can be used in outdoor applications because of lower density